2010 - 2012
HELYOS-High pErformance modeLling of hYbrid Organic Solar Cells (understanding the mechanism, improving the efficiency)
Principal Investigator: 
Fabrizio Santoro
Project type: 


Dye-sensitized Solar Cells (DSC), introduced by M. Graetzel in 1991 have reached a remarkable high solar to electric power conversion efficiency currently exceeding 11%. For further progress of DSC technology higher conversion efficiencies need to be achieved. To this end, new sensitizers and nanostructured materials and a deeper understanding of the interaction between the dye and the nanostructured oxide heterointerface are essential. Theoretical modelling can be of great help in the design and molecular engineering of new solar cells sensitizers and nanostructured semiconductor oxides with improved characteristics. In this project the Pisa Research Unit (RU) will tackle two main objectives: (i) the study of the absorption and emission band shape of candidate dyes and, (ii) the study of the nonadiabatic process of charge separation/recombination processes . Concerning (i) we point at a full ab-inition simulation of the electronic spectra through proper inclusion of vibronic effects and inhomogenoeus broadening . These simulations will be performed thanks to the time-independent FCclasses method, recently developed in our labs. For very large systems we plan the development of more effective proper analytical time-dependent schemes which avoid the computation of the individual vibronic transitions and their summation, allowing the direct computation of the resulting convoluted spectra, also including the temperature effect. As far as (ii) is concerned, the study of the nonadiabatic dynamics of charge separation/recombination processes will be tackled on the ground of suitable vibronic models, through the multiconfigurational time dependent Hartree (MCTDH) method. Vibronic models, including the main orbitals (or the semiconductor conduction band) and the main degrees of freedom will be derived from explorative quantum calculations. To make the dynamical problem tractable a proper generalization of the hierarchical electron-phonon models will be needed for the reduction of the degrees of freedom of the system, through effective and rigorous selection schemes. National coordinator of the Project is Dr. Filippo de Angelis ISTM-CNR (filippo@thch.unipg.it)